Using the table of average bond energies below, the AH for the reaction is KJ. HH H-CEC-H(g) + 2HI (g) → I-C-C-I(g) HH Bond: C=C C-C H-I C-I C-H D 839 348 299 240 413 (kJ/mol): -217 -160 +63 +160 -63

Calculate the enthalpy change when 1.0(1 g of methane is burned in excess oxygen according to the reaction CH,(g) 4- 2O2(g) ->CO2(g) + H-CH/) 1H = -891 kJ/mol

A 0.470-g sample of magnesium reacts with 200 g dilute HCl in a coffee-cup calorimeter to form MgCl2(aq) and H2(g). The temperature increases by 10.9 C as the magnesium reacts. Assume that the mixture has the same specific heat as water and a mass of 200 g. (a) Calculate the enthalpy change for the reaction. Is the process exothermic or endothermic? (b) Write the chemical equation and evaluate H.

The equation for the fermentation of glucose to alcohol and carbon dioxide is: C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The enthalpy change for the reaction is 67 kJ. Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?

1. For the reaction 2 Hg(l) + O2(g) → 2 HgO(s), ∆rH° = 181.6 kJ/mol-rxn. What is the enthalpy change to decompose 1.00 mol of HgO(s) to O2(g) and Hg(l)? 3633 kJ −90.8 kJ 90.8 kJ 363.3 kJ

Write reactions for which the enthalpy change will be a. Hf for solid aluminum oxide. b. the standard enthalpy of combustion of liquid ethanol, C2H5OH(l). c. the standard enthalpy of neutralization of sodium hydroxide solution by hydrochloric acid. d. Hf for gaseous vinyl chloride, C2H3Cl(g). e. the enthalpy of combustion of liquid benzene, C6H6(l). f. the enthalpy of solution of solid ammonium bromide.

The heat of neutralization, Hneut, can be defined as the amount of heat released (or absorbed), q, per mole of acid (or base) neutralized. Hneut for nitric acid is -52 kJ/mol HNO3. At 27.3C, 50.00 mL of 0.743M HNO3 is neutralized by 1.00 M Sr(OH)2 in a coffee-cup calorimeter. (a) How many mL of Sr(OH)2 were used in the neutralization? (b) What is the final temperature of the resulting solution? (Use the assumptions in Question 11.)

A 50-mL solution of a dilute AgNO3 solution is added to 100 mL of a base solution in a coffee-cup calorimeter. As Ag2O(s) precipitates, the temperature of the solution increases from 23.78 C to 25.19 C. Assuming that the mixture has the same specific heat as water and a mass of 150 g, calculate the heat q. Is the precipitation reaction exothermic or endothermic?

What mass of acetylene, C2H2(g), must be burned to produce 3420 kJ of heat, given that its enthalpy of combustion is 1301 kJ/mol? Compare this with the answer to Exercise 5.91 and determine which substance produces more heat per gram.

When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?